# Websocket Compression

URL: /docs/features/websocket-compression/
Section: features

--------------------------------------------------------------------------------

WebSocket Compression Pounce supports permessage-deflate compression for WebSocket connections, reducing bandwidth usage by 60-80% for text messages with repetitive content (JSON, HTML, etc.). Configuration WebSocket compression is enabled by default: from pounce import ServerConfig config = ServerConfig( websocket_compression=True, # Default: True websocket_max_message_size=10_485_760, # 10 MB (default) ) How It Works Negotiation: When a client requests Sec-WebSocket-Extensions: permessage-deflate, pounce automatically negotiates and responds with the same header in the 101 response. Transparent: Compression and decompression are handled automatically by wsproto. Your ASGI app sends/receives uncompressed data—pounce handles the compression at the protocol layer. Per-Message: Each WebSocket message is compressed independently, allowing for efficient streaming and minimal memory overhead. Benefits Bandwidth Savings: 60-80% reduction for text data (JSON, HTML, XML) Lower Latency: Smaller payloads = faster transmission over slow networks Mobile-Friendly: Reduces data usage for mobile clients Zero App Changes: Works transparently with existing ASGI WebSocket apps Example # Your ASGI app doesn't change—compression is automatic async def websocket_app(scope, receive, send): if scope["type"] == "websocket": await send({"type": "websocket.accept"}) # Send a large JSON payload—automatically compressed data = {"users": [...]} # Large JSON object await send({"type": "websocket.send", "text": json.dumps(data)}) await send({"type": "websocket.close"}) Performance Compression adds minimal CPU overhead (< 5% for typical workloads) while providing significant bandwidth savings: Message Type Uncompressed Compressed Ratio JSON (repetitive keys) 10 KB 2-3 KB 70-80% HTML fragments 5 KB 1-2 KB 60-80% Random data 10 KB ~10 KB 0% Disabling Compression To disable compression (e.g., for already-compressed data like images or encrypted content): config = ServerConfig(websocket_compression=False) Requirements WebSocket compression requires the wsproto library: pip install pounce[ws] Compatibility Permessage-deflate is widely supported: All modern browsers (Chrome, Firefox, Safari, Edge) Node.js ws library Python websockets library Go gorilla/websocket Spec Compliance Implements RFC 7692 (WebSocket Compression Extensions).

--------------------------------------------------------------------------------

Metadata:
- Word Count: 287
- Reading Time: 1 minutes